CN112010680A

CN112010680A - Microwave dielectric ceramic device and its manufacturing method

Info

Publication number: CN112010680A
Application number: CN201910463490.1A
Authority: CN
Inventors: 王志建; 杨志刚; 张志强
Original assignee: Richview Electronics Co ltd
Current assignee: Richview Electronics Co ltd
Priority date: 2019-05-30
Filing date: 2019-05-30
Publication date: 2020-12-01

Abstract

The invention relates to a microwave dielectric ceramic device and a manufacturing method thereof. A microwave dielectric ceramic device (1) comprises: a ceramic substrate (10) having through slots (11) and/or grooves (12); and a metal layer (20) formed on the surface (13), the bottom (14) and the wall (15) of the groove of the ceramic substrate (10), wherein the bonding force between the metal layer (20) and the ceramic substrate (10) is 1kg/cm²The resistivity of the metal layer (20) is 1.80 [ mu ] omega cm or less. The method for manufacturing the microwave dielectric ceramic device comprises the following steps: pre-treating a ceramic substrate (10) having through slots (11) and/or grooves (12); and on the ceramic substrate (10)A metal layer (20) is formed on the surface (13), the groove bottom (14) and the groove wall (15) so that the bonding force between the metal layer (20) and the ceramic substrate (10) is 1kg/cm²The resistivity of the metal layer is 1.80 [ mu ] omega cm or less.

Description

Microwave dielectric ceramic device and its manufacturing method

Technical Field

The invention relates to a microwave dielectric ceramic device and a manufacturing method thereof. The microwave dielectric ceramic device is designed and manufactured by utilizing the characteristics of low loss, high dielectric constant, small temperature coefficient of resonance frequency and thermal expansion coefficient, high power bearing capacity, small volume and the like of a dielectric ceramic material, works in the range of a microwave band (the frequency is 300 MHz-300 GHz), and can be used in various microwave circuits with specific functions, such as a transmitter, a receiver, an antenna system, a display, a radar, a communication system and the like.

Background

Generally, a microwave dielectric ceramic device includes a ceramic substrate and a metal layer on the substrate, wherein the dielectric constant and dielectric dissipation factor of the ceramic substrate, the conductivity of the metal layer, and the like affect the performance of the ceramic device. For example, a high dielectric constant of the ceramic substrate contributes to miniaturization of the microwave device, a low dielectric dissipation factor contributes to reduction of dielectric loss of the microwave device, and a high conductivity of the metal layer contributes to reduction of conductor loss, thereby improving the quality factor of the microwave dielectric ceramic device, reducing insertion loss of signal transmission, and the like. In addition, the microwave dielectric ceramic device also requires high reliability of the metal layer and the ceramic substrate, i.e. high bonding force between the metal layer and the ceramic substrate, so as to overcome the problem that the metal layer and the ceramic substrate are separated due to internal stress caused by great difference of thermal expansion coefficients of the metal layer and the ceramic substrate in a thermal shock environment (for example, soldering condition at about 260 ℃), thereby causing the performance of the device to fail.

According to the design requirement, the microwave dielectric ceramic device can be formed with a structure of a through groove or a groove, wherein the shape of the notch is circular, rectangular, square and the like, the groove wall is generally a plane or a curved surface, and the depth of the groove is from small to dozens of micrometers to as large as more than 3 millimeters. Both the surface and the channel structure of these shaped ceramic substrates need to be metallized to form a metal layer. When metallizing the groove walls and bottoms of the through grooves and the grooves with large depth, the prior art mainly applies silver paste by a spraying or barrel plating method, and the silver paste is bonded with the ceramic substrate by high-temperature sintering, so that a metal layer is formed. However, it is difficult to achieve metallization of the groove walls and the groove bottoms of the through grooves and the grooves with large depth and small notches (i.e., high aspect ratio) whether silver paste is sprayed or barrel-plated. Moreover, the silver paste used contains additives, so that the conductivity is reduced, a large amount of silver paste waste is generated in the whole process, the utilization rate of the silver paste is reduced, the environmental pollution is increased, and the total cost of the product is increased.

Disclosure of Invention

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a microwave dielectric ceramic device which easily achieves metallization of the groove walls and the groove bottoms of the through grooves and the grooves having a high aspect ratio and has a metal layer having a strong bonding force and a high electrical conductivity, and a method of manufacturing the same.

In one aspect, the present invention provides a microwave dielectric ceramic device comprising: a ceramic substrate having through slots and/or grooves; and a metal layer formed on the surface, bottom and wall of the groove of the ceramic substrate, wherein the bonding force between the metal layer and the ceramic substrate is 1kg/cm²The resistivity of the metal layer is 1.80 [ mu ] omega cm or less.

The binding force between the metal layer and the ceramic substrate is up to 1kg/cm²In addition, the resistivity of the metal layer is as low as 1.80 mu omega cm or less, so that the microwave dielectric ceramic device of the invention has low conductor loss and insertion loss, high quality factor and the like. Moreover, both the metal layer and the ceramic substrate have high reliability, and the metal layer is not easy to separate from the ceramic substrate, so that the performance of the device is not effective.

Optionally, the metal layer includes a metal primer layer attached to the surface of the ceramic substrate, the bottom and walls of the trench, and a metal thickening layer attached to the metal primer layer.

Optionally, the metal base layer comprises a first base layer and a second base layer in sequence from inside to outside, and the first base layer and the second base layer are formed by multi-arc ion plating and have a thickness of 20-200 nm.

In the multi-arc ion plating, the energy and direction of the particle beam can be precisely controlled by an electric field, a magnetic field and the like, and the particle beam has accurate directivity, so that a uniform metal layer is easily formed on the groove bottom and the groove wall of the ceramic device and is not influenced by the groove depth and the groove opening. In addition, by means of the metal thickening layer on the metal bottom layer, the sheet resistance and the conductivity of the whole metal layer can be effectively adjusted to ensure low sheet resistance and high conductivity.

Optionally, the first primer layer is composed of one or more of Cr, Ni, Ti, Mo, W, Sn, and alloys thereof, and the second primer layer is composed of one or more of Ag, Cu, Au, Pt, Al, and alloys thereof.

Optionally, the metal base layer further comprises a third base layer formed on the second base layer by magnetron sputtering, the third base layer being composed of the same material as the second base layer and having a thickness of 1 to 3 μm.

The third underlying layer is formed by magnetron sputtering, so that the sheet resistance and the conductivity of the metal layer can be properly adjusted to reduce the sheet resistance and improve the conductivity. Also, the magnetron sputtering can deposit a primer layer having the same thickness in less time, as compared with the case where the primer layer is formed only by the multi-arc ion plating, thereby improving the deposition efficiency. Furthermore, since the second and third primer layers are composed of the same material, the two primer layers will have similar lattice composition and physical properties therebetween, resulting in a high bonding force therebetween, even between the entire metal layer and the ceramic substrate.

Optionally, the metal thickening layer is a Cu layer formed by electroplating and has a thickness of 4-40 μm.

Compared with the silver paste containing the additive, the electroplated copper layer comprises copper metal with the purity of more than 99%, and the conductivity of the electroplated copper layer is greater than that of the silver paste, so that the conductor loss of a ceramic device can be remarkably reduced, the insertion loss is reduced, and the quality factor is improved.

Optionally, the microwave dielectric ceramic device further comprises a doped layer located below the surface, the bottom and the wall of the groove of the ceramic substrate, the metal bottom layer is attached to the doped layer, and the thickness of the doped layer is less than 10 nm.

Optionally, the microwave dielectric ceramic device further comprises a doped layer located below the surface, the bottom and the walls of the trench of the ceramic substrate, the first primer layer being attached to the doped layer, wherein the doped layer is formed by ion implantation and is composed of the same material as the first primer layer.

During ion implantation, high energy ions treat the surface of the ceramic substrate to create a doped layer at the surface. The doped layer containing metal ions is combined with the metal bottom layer, so that the binding force between the base material and the metal layer is improved. Because the doping layer and the first primer layer are made of the same material and have similar lattice composition and physical properties, the bonding force between the first primer layer and the ceramic substrate, even the whole metal primer layer, can be further improved. In addition, the ion beam energy and direction during ion implantation can be precisely controlled by an electric field and the like, and the ion beam has accurate directivity, so that uniform doped layers are easily formed on the groove bottom and the groove wall of the ceramic substrate and are not influenced by the groove depth and the groove opening.

Alternatively, the microwave dielectric ceramic device includes a ceramic filter, a ceramic resonator, a ceramic amplifier, a ceramic oscillator, a ceramic mixer, a ceramic wave detector, and a ceramic antenna, and the ceramic substrate includes Al₂O₃Silicate, spinel type ceramics, composite perovskite, BaO-TiO₂Is (Zn, Sn) TiO₄Is BaO-TiO₂-Nb₂O₅System, BaO-Ln₂O₃-TiO₂System, lead-based perovskite system, CaO-Li₂O-Ln₂O₃-TiO₂Is a microwave dielectric ceramic.

In another aspect, the present invention also provides a method of manufacturing a microwave dielectric ceramic device, comprising: pretreating a ceramic substrate, wherein the ceramic substrate is provided with a through groove and/or a groove; and forming a metal layer on the surface, bottom and wall of the groove of the ceramic substrate to make the bonding force between the metal layer and the ceramic substrate 1kg/cm²The resistivity of the metal layer is 1.80 [ mu ] omega cm or less.

Optionally, the pre-processing includes: the ceramic substrate is heated to a certain temperature, and then the temperature is maintained to carry out Hall source treatment, so that the treated ceramic substrate has a surface tension coefficient of more than 60 dyn/cm.

The heat treatment can discharge air and moisture on the surface and inside of the ceramic substrate, promote the bonding between the metal layer and the ceramic substrate, and improve the bonding force therebetween. Through Hall source processing, can wash away the organic matter on ceramic surface, improve ceramic substrate's surface activity to improve the cohesion between metal level and the ceramic substrate.

Optionally, forming the metal layer comprises: through multi-arc ion plating, a first bottoming layer is formed on the surface, the groove bottom and the groove wall of the ceramic substrate by using a first material, and then a second bottoming layer is formed on the first bottoming layer by using a second material, wherein the first bottoming layer and the second bottoming layer form a metal bottoming layer.

Optionally, forming the metal layer further comprises: and forming a third base coat layer on the second base coat layer by utilizing the second material through magnetron sputtering, wherein the first base coat layer, the second base coat layer and the third base coat layer form a metal base coat layer.

Optionally, the method further includes: before forming the first primer layer, a first material is implanted into the surface of the ceramic substrate, the bottom of the trench and under the trench walls by ion implantation to form a doped layer, wherein the doped layer has a thickness of 10nm or less.

Optionally, the first material is selected from one or more of Cr, Ni, Ti, Mo, W, Sn and alloys thereof, the second material is selected from one or more of Ag, Cu, Au, Pt, Al and alloys thereof, the thickness of the first underlayer and the second underlayer is 20-200 nm, and the thickness of the third underlayer is 1-3 μm.

Optionally, forming the metal layer further comprises: forming a metal thickening layer on the metal base layer by electroplating, wherein the metal thickening layer is composed of Cu and has a thickness of 4-40 μm.

Drawings

These and other features, aspects, and advantages of the present invention will become more readily apparent to those skilled in the art after reading the following detailed description, with reference to the accompanying drawings. For purposes of clarity, the drawings are not necessarily to scale, and certain parts may be exaggerated to show details. The same reference numbers will be used throughout the drawings to refer to the same or like parts, wherein:

FIG. 1(a) shows a schematic cross-sectional view of a ceramic substrate in a first embodiment of the invention;

fig. 1(b) is a schematic cross-sectional view showing a first primer layer formed on a ceramic substrate in a first embodiment of the present invention;

FIG. 1(c) is a schematic sectional view showing a case where a second primer layer is formed on a ceramic substrate in the first embodiment of the present invention;

FIG. 1(d) is a schematic sectional view showing a third primer layer formed on a ceramic substrate in the first embodiment of the present invention;

FIG. 1(e) is a schematic cross-sectional view of a microwave dielectric ceramic device with a metal thickening layer formed on a ceramic substrate in a first embodiment of the present invention;

FIG. 2(a) shows a schematic cross-sectional view of a ceramic substrate in a second embodiment of the invention;

FIG. 2(b) is a schematic cross-sectional view showing a case where a doped layer is formed in a ceramic substrate in a second embodiment of the present invention;

fig. 2(c) is a schematic sectional view showing a first primer layer formed on a ceramic substrate in a second embodiment of the present invention;

FIG. 2(d) is a schematic cross-sectional view showing a second primer layer formed on a ceramic substrate in a second embodiment of the present invention;

FIG. 2(e) is a schematic sectional view showing a third primer layer formed on a ceramic substrate in a second embodiment of the present invention;

fig. 2(f) is a schematic cross-sectional view of a microwave dielectric ceramic device in a second embodiment of the present invention, when a metal thickening layer is formed on a ceramic substrate.

Reference numerals:

1. 2 microwave dielectric ceramic device

10 ceramic substrate

11 through groove

12 grooves

13 surface of

14 groove bottom

15 groove wall

16 doped layer

20 metal layer

21 metal primer layer

22 first primer layer

23 second primer layer

24 third base coat

25 thickening layers of metal.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood by those skilled in the art that these descriptions are merely illustrative of exemplary embodiments of the present invention and are not intended to limit the scope of the present invention in any way. For example, elements or features depicted in one drawing or embodiment of the invention may be combined with other elements or features depicted in one or more other drawings or embodiments. Furthermore, for convenience in describing the positional relationship between the various material layers, spatially relative terms such as "upper" and "lower," as well as "inner" and "outer," etc., are used herein with respect to the surface or walls of the grooves of the substrate. For example, if a material is located in a direction toward the exterior of the substrate relative to another material, the other material is said to be "on" or "out" of the material, and vice versa.

Fig. 1(a) to 1(e) show embodiment 1 of the present invention, and fig. 2(a) to 2(f) show embodiment 2 of the present invention. Hereinafter, a method of manufacturing a microwave dielectric ceramic device according to the present invention, and a microwave dielectric ceramic device manufactured by the method will be described in detail with reference to the accompanying drawings. The method of the present invention generally includes two steps of "pre-treating the ceramic substrate" and "forming a metal layer on the ceramic substrate", wherein each step may in turn include a series of specific processes, as described below.

(example 1)

Fig. 1(a) shows a schematic cross-sectional view of a ceramic substrate 10. The ceramic substrate 10 may have various shapes such as a square, a rectangular parallelepiped, a polyhedron, a truncated cone, a cone, etc., but is shown as a rectangular parallelepiped in the drawing, according to the design requirements of the microwave dielectric ceramic device. As shown in fig. 1(a), the ceramic substrate 10 has a through groove 11 and a groove 12, wherein the through groove 11 and the groove 12 each have a groove wall 15, and the groove 12 further has a groove bottom 14. The ceramic substrate 10 also has a surface 13 including an upper surface, a lower surface, and a side surface in the circumferential direction. These groove walls 15, groove bottoms 14 and surfaces 13 may comprise flat or curved surfaces, such as cylindrical or rounded, convex or concave surfaces, etc. The shape of the notch may be circular, rectangular, square, etc., and the depth of the groove may be as small as several tens of micrometers, for example, 50 μm, or as large as more than 3 mm, for example, 5 mm. In some embodiments, the ceramic substrate 10 may have only the through-grooves 11, or only the grooves 12, and these through-grooves 11 or grooves 12 may be two or more.

Generally, the ceramic substrate used for microwave dielectric ceramic devices is a dielectric ceramic material, and has the characteristics of low loss, high dielectric constant, low frequency temperature coefficient and thermal expansion coefficient, high bearable power, small volume and the like. Dielectric ceramic materials that satisfy these conditions may include, for example: BaO-Ln of tungsten bronze structure₂O₃~TiO₂(BLT) series, CaTiO₃Modified series, modified lead-based perovskite series and the like, which are mainly used as dielectric resonators in civil mobile communication systems in low frequency ranges; with BaTi₄O₉、Ba₂Ti₉O₂₀And (Zr, Sn) TiO₄Microwave dielectric ceramic material based on the same, low dielectric constant material and CaTiO₃、SrTiO₃The composite material is mainly used as a dielectric resonator in microwave military radars and communication systems in a medium frequency range; and composite perovskite structure type materials, mainly used for microwave dielectric ceramics in a high frequency range. More specifically, the ceramic substrate 10 of the present invention may include: low dielectric constant microwave medium with dielectric constant less than 30Ceramics, e.g. Al₂O₃Silicate, spinel, composite perovskite, and the like; a medium dielectric constant microwave dielectric ceramic having a dielectric constant of 30 to 70, such as BaO-TiO₂Is (Zn, Sn) TiO₄Is BaO-TiO₂-Nb₂O₅And the like; and high dielectric constant microwave dielectric ceramics having a dielectric constant greater than 70, e.g. BaO-Ln₂O₃-TiO₂System (Ln)₂O₃Is + 3-valent metal oxide), lead-based perovskite system, CaO-Li₂O-Ln₂O₃-TiO₂System (Ln)₂O₃Is a +3 valent metal oxide), and the like. In addition, many other types of ceramic materials may be used in the ceramic substrate 10.

When manufacturing microwave dielectric ceramic devices, the ceramic substrate, in particular the surface, the bottom and the walls of the groove, are first pretreated. For example, ceramic substrates may be heat treated in various furnaces, with the temperature and time of the heat treatment being adjusted according to the type of substrate and the performance requirements of the final device. In one embodiment, the temperature range of the heating treatment may be 150 to 400 ℃, and the time of the heating treatment may be 5 to 30 minutes. The heat treatment can discharge air and moisture existing on the surface and inside of the ceramic base material, and is advantageous for improving the bonding force between the metal layer and the ceramic base material, which will be described later. In addition, the ceramic substrate is kept at a certain temperature range (for example, 150-400 ℃) for a period of time, which is helpful for the growth and nucleation of a metal layer on the surface of the ceramic substrate, and thus the bonding force is further improved.

After the temperature is kept for a period of time, the Hall ion source is opened, the ceramic substrate is continuously pretreated, and the ceramic substrate is still in a heat-preservation state at the moment. The Hall ion source ionizes gas filled in a vacuum chamber under the interaction of an electric field and a magnetic field by utilizing emitted electrons in a vacuum environment, and emits ions under the action of the electric field and the magnetic field. During the hall source process, the voltage, current, and process time, etc., can be adjusted according to the type of substrate and the performance requirements of the final device. In one embodiment, the voltage processed by the Hall source is 1000-2000V, the current is 0.1-2A, and the processing time is 5-20 minutes. The Hall source treatment can clean organic matters on the surface of the ceramic, improve the surface activity of the ceramic substrate, for example, the surface tension coefficient of the treated ceramic substrate can reach more than 60dyn/cm, even more than 80dyn/cm, and improve the binding force between the metal layer and the ceramic substrate.

Then, a first primer layer 22 is formed on the surface 13, the groove bottom 14, and the groove wall 15 of the ceramic substrate 10 by multi-arc ion plating, as shown in fig. 1 (b). The multi-arc ion plating uses arc discharge, uses a cathode target as an evaporation source, and evaporates a target material by arc discharge between the cathode target and an anode casing to form plasma in a processing space and deposit a base material. In the multi-arc ion plating, plasma is directly generated from a cathode without using a molten pool, so that cathode targets can be arranged in any direction according to the shape of a workpiece, and a jig can be greatly simplified. Moreover, the multi-arc ion plating has the advantages of high evaporation rate, high incident particle energy, high film density, good strength and durability, good adhesion strength and high ionization rate which can generally reach 60-80%. In addition, the energy and the direction of particle beams during multi-arc ion plating deposition can be precisely controlled by an electric field, a magnetic field and the like, and the particle beams have accurate directionality, so that uniform metal layers can be formed on the groove bottom and the groove wall of the ceramic device with a high depth-to-width ratio and are not influenced by the groove depth and the groove opening.

The first undercoat layer 22 may be formed using Cr, Ni, Ti, Mo, W, Sn, etc., or an alloy composed of one or more elements among them, such as Ni — Cr, Ti — Cr alloy, etc. In addition, other metals, alloys, conductive oxides, conductive carbides, conductive organics, and the like may be used as the conductive material, and a material having a strong bonding force with the ceramic substrate is preferable. During multi-arc ion plating, the current, voltage, deposition time, etc. may be adjusted according to the type of substrate and the bonding force requirements. In one embodiment, the deposition current of the multi-arc ion plating is 45-70A, the extraction current is 6-15A, the bias electric field is 5-20V, and the deposition time is 2-30 minutes. The current range of 45-70A is beneficial to improving the concentration of ion beam current, the extraction current of 6-15A is beneficial to improving the deposition efficiency, the bias electric field of 5-20V is beneficial to improving the energy of ion beams and increasing the binding force between the first priming layer and the ceramic substrate, and the multi-arc ion plating deposition time of 2-30 minutes is beneficial to improving the thickness of the first priming layer so as to meet the requirement of sheet resistance. In one embodiment, the thickness of the first primer layer 22 may be 20 to 200nm, such as 50nm, 100nm, or 150 nm.

Next, continuing through the multi-arc ion plating, a second primer layer 23 is formed over the first primer layer 22 that has been formed on the surface 13, the groove bottom 14, and the groove wall 15 of the ceramic base material 10, as shown in fig. 1 (c). In this process, the multi-arc ion plating can be performed under the same conditions as those used for forming the first primer layer 22, i.e., a deposition current range of 45 to 70A, an extraction current of 6 to 15A, a bias electric field of 5 to 20V, and a deposition time of 2 to 30 minutes. The second primer layer 23 is composed of a different material from the first primer layer 22. For example, Ag, Cu, Au, Pt, Al, or the like, or an alloy composed of one or more elements among them may be used to form the second underlying layer 23. The elements or the alloy have high conductivity, and are beneficial to reducing conductor loss, so that the quality factor of the microwave dielectric ceramic device is improved, the insertion loss of signal transmission is reduced, and the like. In one embodiment, the thickness of the second primer layer 23 may be 20 to 200nm, such as 50nm, 100nm, or 150 nm. The thickness of the second primer layer 23 may be the same as or different from that of the first primer layer 22.

After the first and second primer layers 22, 23 are formed by multi-arc ion plating, the process is ended. Subsequently, by the magnetron sputtering technique, a third underlying layer 24 is continuously formed over the second underlying layer 23, as shown in fig. 1 (d). The first primer layer 22, the second primer layer 23, and the third primer layer 24 may be collectively referred to as "the metal primer layer 21" as a part of the metal layer 20. In the magnetron sputtering process, electrons collide with argon atoms in the process of flying to the substrate under the action of an electric field, so that the argon atoms are ionized to generate Ar⁺Ions and new electrons, wherein the new electrons fly towards the substrate, Ar⁺Ions are accelerated to fly to the cathode target under the action of an electric field and bombard the surface of the target with high energy, so that the target is sputtered. Any suitable conductive material may be used to form the third layerA primer layer 24. In one embodiment, magnetron sputtering uses the same material as the second underlying layer 23 to form the third underlying layer 24, i.e., Ag, Cu, Au, Pt, Al, or the like or an alloy composed of one or more elements among them. In this way, the third and second primer layers will have similar lattice compositions and physical properties resulting in a high bonding force between the two primer layers, and even between the entire metal layer and the ceramic substrate. Of course, the third primer layer 24 may be formed using a different material from the second primer layer 23. In addition, during magnetron sputtering, the current and deposition time, etc. can be adjusted according to the requirements on the thickness and conductivity of the metal underlayer. In one embodiment, the magnetron sputtering current is 0.5-10A, and the deposition time is 2-30 minutes. Such conditions contribute to increase the thickness of the metal primer layer 21, further reducing the sheet resistance thereof, and thus improving the conductivity. In one embodiment, the thickness of the third primer layer 24 may be 1-3 μm, such as 1.5 μm, 1.95-1.98 μm, 2.5 μm, etc.

Thereafter, the ceramic substrate 10 on which the metal primer layer 21 has been formed is put into a plating apparatus to be plated, thereby forming a metal thickening layer 25 on the metal primer layer 21, as shown in fig. 1 (e). In this process, various methods such as rack plating, barrel plating, continuous plating, brush plating, and the like can be appropriately selected according to the size, shape, lot, and the like of the ceramic base material 10, and various techniques and processes such as cyanide copper plating, sulfate copper plating, pyrophosphate copper plating, cyanide-free copper plating, and the like can be selected to perform copper plating on the surface of the metal primer layer 21. The plating technique can be applied to Ni, Sn, Ag, and alloys thereof, etc., in addition to copper (Cu), and is used to form these metals or alloys over the metal underlying layer 21. In addition to electroplating techniques, one or more of electroless plating, sputtering, vacuum evaporation plating, and the like may be used to form the metal thickening layer 25. The thickness of the metal thickening layer can be conveniently and easily adjusted by adjusting the current, the working time and the like in the technical processes of electroplating and the like.

In one embodiment, the same material as the third underlying layer 24 is used, such as Ag, Cu, Au, Pt, Al, etc., or from among themAn alloy of one or more elements to form metal thickening layer 25. In one embodiment, the metal thickening layer is formed by electroplating at a current density of 1A/dm²(i.e., 1asd), the plating time is 30 to 100 minutes. The small current, long time electroplating is helpful to improve the thickness uniformity on the surface of the substrate and the groove wall and groove bottom. In one embodiment, the metal thickening layer 25 is an electroplated copper layer, which may have a thickness of 4-40 μm, such as 5 μm, 10 μm, 20 μm, 30 μm, 35 μm, and the like. Generally, the electroplated copper layer includes copper metal with a purity of more than 99%, and has a conductivity greater than that of a conventional silver paste containing an additive, thereby significantly reducing conductor loss, reducing insertion loss, and improving quality factor of the ceramic device.

The metal base layer 21 and the metal thickening layer 25 together form a metal layer 20, and the bonding force between the metal layer 20 and the ceramic substrate 10 is 1kg/cm²The resistivity of the metal layer 20 is 1.80 [ mu ] omega cm or less. In some embodiments, the bonding force between the metal layer 20 and the ceramic substrate 10 may be 1.5kg/cm²Above, even up to 2kg/cm²While the resistivity of the metal layer 20 may be 1.50 μ Ω · cm or less, even as low as 1.0 μ Ω · cm or less. Therefore, the microwave dielectric ceramic device of the present embodiment has lower conductor loss and insertion loss, and higher quality factor, etc., while also having higher reliability, in which the metal layer is not easily separated from the ceramic substrate to deteriorate the performance of the device.

After the metal layer is formed, the microwave dielectric ceramic device may be subjected to post-treatment, such as annealing treatment to eliminate the stress existing therein and prevent the metal layer from cracking, or surface passivation treatment to prevent the metal layer from being oxidized in air.

Fig. 1(e) shows a microwave dielectric ceramic device 1 according to example 1 of the present invention, which is prepared by the above-described method. As shown, the device 1 comprises: a ceramic substrate 10 having a through groove 11 and a groove; and a metal layer 20 formed on the surface 13, the groove bottom 14, and the groove wall 15 of the ceramic substrate 10. The metal layer 20 includes a metal primer layer 21 attached to the surface 13, the groove bottom 14 and the groove wall 15 of the ceramic substrate 10, and a metal thickening layer 25 attached to the metal primer layer 21. The metal primer layer 21 includes a first primer layer 22, a second primer layer 23, and a third primer layer 24 in this order from the inside to the outside. The microwave dielectric ceramic device 1 can be applied to devices working in a microwave band (with the frequency of 300 MHz-300 GHz), such as a ceramic filter, a ceramic resonator, a ceramic amplifier, a ceramic oscillator, a ceramic mixer, a ceramic detector, a ceramic antenna and the like.

(example 2)

Fig. 2(a) to 2(f) show embodiment 2 of the present invention, which embodiment 2 differs from embodiment 1 described above in that: after the pretreatment process and before the formation of the metal primer layer, doped layers are formed on the surface of the ceramic substrate, below the groove bottom and the groove wall. Next, the process of this embodiment will be described in detail.

Fig. 2(a) shows a ceramic substrate 10 for a microwave dielectric ceramic device. The ceramic substrate 10 is the same as the ceramic substrate shown in fig. 1(a), and has a surface 13, a through groove 11, and a groove 12, wherein the through groove 11 and the groove 12 each have a groove wall 15, the groove 12 further has a groove bottom 14, and the surface 13 includes an upper surface, a lower surface, and a side surface in the circumferential direction, and the like. In some embodiments, the ceramic substrate 10 may have only the through-grooves 11, or only the grooves 12, and these through-grooves 11 or grooves 12 may be two or more.

In the manufacture of a microwave dielectric ceramic device, a ceramic substrate is first subjected to a pretreatment. The pretreatment comprises heating treatment and Hall source treatment. During the heat treatment, the temperature and time of the heat treatment can be adjusted according to the type of substrate and the performance requirements of the final device. In one embodiment, the temperature range of the heating treatment is 150-200 ℃, and the time of the heating treatment is 5-30 minutes. The heat treatment can discharge air and moisture existing on the surface and inside of the ceramic base material, and is advantageous for improving the bonding force between the metal layer and the ceramic base material, which will be described later. During the hall source process, the voltage, current, and processing time, etc. can be adjusted according to the type of substrate and the performance requirements of the final device. In one embodiment, the voltage processed by the Hall source is 1000-2000V, the current is 0.1-2A, and the processing time is 5-20 minutes. Through the Hall source treatment, organic matters on the surface of the ceramic can be cleaned, the surface activity of the ceramic substrate is improved, for example, the surface tension coefficient of the treated ceramic substrate can reach more than 60dyn/cm, even more than 80dyn/cm, and the binding force between the metal layer and the ceramic substrate is improved.

After the pretreatment is completed, a conductive material is implanted by ion implantation under the surface 13, the groove bottom 14 and the groove wall 15 of the ceramic substrate 10 to form a doped layer. In the ion implantation process, a conductive material is used as a target material, the conductive material in the target material is ionized under the action of electric arc in a vacuum environment to generate ions, and then the ions are accelerated under a high-voltage electric field to obtain high energy; the energetic ions of the conductive material impinge at high velocity directly onto the surface, trough bottom or trough walls of the substrate and are implanted to a depth below these surfaces, trough bottom or trough walls. As shown in fig. 2(b), the substrate 10 after the ion implantation treatment has a doped layer 16, the outer surface of the doped layer 16 is flush with the surface 13, the groove bottom 14 and the groove wall 15 of the substrate 10, and the inner surface is deep into the substrate 10. In fact, the implanted particles of conductive material may form stable chemical bonds, such as ionic or covalent bonds, in the material lattice of the substrate, which together constitute a doped structure, as in semiconductors. The chemical bond is helpful for enhancing the binding force between the doping layer and the substrate, so that the doping layer and a metal layer or a bottom layer attached to the doping layer are not easy to fall off from the substrate. In addition, the ion beam energy and direction during ion implantation can be precisely controlled by an electric field and the like, and the ion beam has accurate directivity, so that uniform doped layers can be formed at the groove bottom and the groove wall of the ceramic substrate with high aspect ratio without being influenced by the groove depth and the groove opening.

Various metals, alloys, conductive oxides, conductive carbides, conductive organics, etc. can be used as targets for the ion implantation process, preferably materials with strong bonding force with the ceramic substrate. In one embodiment, the target material for ion implantation is the same as the composition material of the first underlayer described later, i.e., Cr, Ni, Ti, Mo, W, Sn, or the like, or an alloy composed of one or more elements thereof, such as Ni — Cr, Ti — Cr alloy, or the like.

The process parameters of the ion implantation process may be determined based on the type of target and substrate used, the desired amount of bonding force, the desired thickness of the doped layer, etc. The voltage of the ion implantation determines the thickness of the doped layer, i.e., the depth of the target ions into the substrate, and the current and time of the ion implantation determine the concentration of ions within the doped layer. In addition to the voltage, the thickness of the doped layer will also vary with the type of target and substrate. By increasing the voltage, the thickness of the doped layer can be increased. By increasing the current and time, the concentration of the doped layer ions can be increased. In one embodiment, the voltage during ion implantation is 10kV to 30kV, the current is 1mA to 5mA, and the treatment time is 2 to 30 minutes. In one embodiment, the thickness of the doped layer is 10nm or less, for example 8nm or 5 nm. That is, the target ions may acquire energies of 10 to 30keV (e.g., 15keV, 20keV, 25keV, etc.) during ion implantation, and may be implanted into a depth range of 0 to 10nm (e.g., 8nm, 5nm, etc.) below the surface 13, the trench bottom 14, and the trench walls 15 of the substrate 10. In addition, in the case of including the doped layer, the heating temperature at the time of the pretreatment can be appropriately lowered, and for example, the maximum temperature can be lowered from 400 ℃ in example 1 to 200 ℃ in example 2. The heating time in the pretreatment can be reduced to 5 to 20 minutes from 5 to 30 minutes in example 1.

After the doped layer 16 is formed, a first primer layer 22 is formed on the surface 13, the groove bottom 14 and the groove wall 15 of the ceramic substrate 10 by the multi-arc ion plating described above. As shown in fig. 2(c), the first primer layer 22 adheres to the doped layer 16 and over the surface 13, the trench bottom 14 and the trench walls 15 of the ceramic substrate 10. The first underlayer 22 may be formed using the same material as the doped layer 16, i.e., Cr, Ni, Ti, Mo, W, Sn, etc., or an alloy composed of one or more elements among them, such as Ni-Cr, Ti-Cr alloy, etc. In this way, the first primer layer and the doped layer have similar lattice composition and physical properties, resulting in the first primer layer being firmly attached to the doped layer, and thus having a high bonding force between the metal primer layer and the ceramic substrate. Of course, a different material from the doped layer 16 may be used to form the first primer layer 22. In one embodiment, the multi-arc ion plating has a deposition current range of 45-70A, an extraction current range of 6-15A, a bias electric field range of 5-20V, and a deposition time of 2-30 minutes, so as to increase the energy of the ion beam and increase the bonding force between the first primer layer and the ceramic substrate and between the first primer layer and the doped layer. In one embodiment, the thickness of the first primer layer 22 may be 20 to 200nm, such as 50nm, 100nm, or 150 nm.

Then, continuing through the multi-arc ion plating, a second primer layer 23 is formed over the first primer layer 22, as shown in fig. 2 (d). In this process, the multi-arc ion plating can be performed under the same conditions as those used for forming the first primer layer 22, i.e., a deposition current range of 45 to 70A, an extraction current of 6 to 15A, a bias electric field of 5 to 20V, and a deposition time of 2 to 30 minutes. The deposition current of 45-70A is beneficial to improving the concentration of ion beam current, the extraction current of 6-15A is beneficial to improving the deposition efficiency, the bias electric field of 5-20V is beneficial to improving the energy of ion beams and increasing the bonding force between the second bottom layer and the first bottom layer, and the deposition time of 2-30 min is beneficial to increasing the thickness of the second bottom layer so as to meet the requirement of sheet resistance.

The second primer layer 23 is composed of a different material from the first primer layer 22. For example, Ag, Cu, Au, Pt, Al, or the like, or an alloy composed of one or more elements among them may be used to form the second underlying layer 23. The elements or the alloy have high conductivity, and are beneficial to reducing conductor loss, so that the quality factor of the microwave dielectric ceramic device is improved, the insertion loss of signal transmission is reduced, and the like. In one embodiment, the thickness of the second primer layer 23 may be 20 to 200nm, such as 50nm, 100nm, or 150 nm. The thickness of the second primer layer 23 may be the same as or different from that of the first primer layer 22.

After the doped layer 16, the first primer layer 22, and the second primer layer 23 are formed, next, by magnetron sputtering, a third primer layer 24 is continuously formed over the second primer layer 23, as shown in fig. 2 (e). Among them, the first primer layer 22, the second primer layer 23, and the third primer layer 24 may be collectively referred to as "metal primer layer 21" as a part of the metal layer 20. In one embodiment, the third underlying layer 24 is formed using the same material as the second underlying layer 23, such as Ag, Cu, Au, Pt, Al, or the like, or an alloy composed of one or more elements among them. In this way, the third and second primer layers will have similar lattice compositions and physical properties resulting in a high bonding force between the two primer layers, and even between the entire metal layer and the ceramic substrate. Of course, the third primer layer 24 may be formed using a different material from the second primer layer 23. In one embodiment, the magnetron sputtering current is 0.5-10A, and the deposition time is 2-30 minutes. By magnetron sputtering, the thickness of the metal primer layer 21 can be effectively increased, and the sheet resistance thereof can be further reduced, thereby improving the conductivity. In one embodiment, the thickness of the third primer layer 24 may be 1-3 μm, such as 1.5 μm, 1.95-1.98 μm, 2.5 μm, etc.

Then, the ceramic substrate 10 on which the metal primer layer 21 has been formed is put into a plating apparatus to be plated, thereby forming a metal thickening layer 25 on the metal primer layer 21, as shown in fig. 2 (f). The plating technique can be applied to Cu, Ni, Sn, Ag, an alloy thereof, and the like, and is used to form these metals or alloys over the metal primer layer 21. In one embodiment, the metal thickening layer 25 may be formed using the same material as the third underlying layer 24, for example, Ag, Cu, Au, Pt, Al, or the like, or an alloy composed of one or more elements among them. In one embodiment, the metal thickening layer 25 is an electroplated copper layer, which may have a thickness of 4-40 μm, such as 5 μm, 10 μm, 20 μm, 30 μm, 35 μm, and the like. In one embodiment, the current density at which the electroplated copper layer is formed is 1A/dm²(i.e., 1asd), the plating time is 30 to 100 minutes. The small current and long-time electroplating is beneficial to improving the thickness uniformity of the copper layer on the surface of the base material, the groove wall and the groove bottom. Generally, the electroplated copper layer includes copper metal with a purity of more than 99%, and has a conductivity greater than that of a conventional silver paste containing an additive, thereby significantly reducing conductor loss, reducing insertion loss, and improving quality factor of the ceramic device.

The metal base layer 21 and the metal thickening layer 25 together form a metal layer 20, and the bonding force between the metal layer 20 and the ceramic substrate 10 is 1kg/cm²The resistivity of the metal layer 20 is 1.80 [ mu ] omega cm or less. Since the doped layer is formed by the ion implantation technique in embodiment 2, the bonding force between the metal layer 20 and the ceramic substrate 10 can be greater than that in embodiment 1, and the conductivity of the metal layer 20 can be higher. For example, in some embodiments, the bonding force between the metal layer 20 and the ceramic substrate 10 may be 1.5kg/cm²Above, even up to 2kg/cm²Or 3kg/cm²The above. The resistivity of the metal layer 20 may be 1.50 μ Ω · cm or less, or even as low as 1.0 μ Ω · cm, or 0.8kg/cm²The following. Therefore, the microwave dielectric ceramic device of the present embodiment has lower conductor loss and insertion loss, and higher quality factor, etc., while also having higher reliability, in which the metal layer is not easily separated from the ceramic substrate to deteriorate the performance of the device.

Fig. 2(f) shows a microwave dielectric ceramic device 2 according to example 2 of the present invention, which is prepared by the above-described method. The device 2 comprises: a ceramic substrate 10 having a through groove 11 and a groove; and a metal layer 20 formed on the surface 13, the groove bottom 14, and the groove wall 15 of the ceramic substrate 10. Wherein the ceramic substrate 10 further comprises a doped layer 16 below its surface 13, the bottom 14 of the trench and the walls 15 of the trench. The metal layer 20 further includes a metal primer layer 21 over the surface 13, the trench bottom 14 and the trench walls 15 of the ceramic substrate 10 and attached to the doped layer 16, and a metal thickening layer 25 attached to the metal primer layer 21. The metal primer layer 21 includes a first primer layer 22, a second primer layer 23, and a third primer layer 24 in this order from the inside to the outside. The microwave dielectric ceramic device 1 can be applied to devices working in a microwave band (with the frequency of 300 MHz-300 GHz), such as a ceramic filter, a ceramic resonator, a ceramic amplifier, a ceramic oscillator, a ceramic mixer, a ceramic detector, a ceramic antenna and the like.

The foregoing description has been directed to only specific embodiments of this invention. However, the invention is not limited to the specific embodiments described herein. Those skilled in the art will readily appreciate that various obvious modifications, adaptations, and alternatives may be made to the embodiments to adapt them to particular situations without departing from the spirit of the present invention. Indeed, the scope of the invention is defined by the claims and may include other examples that may occur to those skilled in the art.

For example, although in the two specific embodiments described above, the first and second primer layers of the metal primer layers are formed by multi-arc ion plating, the second primer layer may not be formed, but a third primer layer may be formed directly above the first primer layer by magnetron sputtering, the metal primer layer being constituted by the first and third primer layers. In addition, instead of forming the third underlying layer by magnetron sputtering, a metal thickening layer may be formed by electroplating directly on top of the first underlying layer and the second underlying layer formed by multi-arc ion plating, and the metal layer may be formed of the first underlying layer, the second underlying layer, and the metal thickening layer. When the doped layer is formed, the metal underlayer may be formed of a second underlayer by multi-arc ion plating and/or a third underlayer by magnetron sputtering, instead of the first underlayer. Further, the doped layer may include not only one layer but two or more layers. For example, Ni or Ni — Ti alloy may be implanted into the surface, bottom, and under the walls of the groove of the ceramic substrate after the previous treatment, followed by Cr ion implantation into the Ni or Ni — Ti alloy layer, followed by multi-arc ion plating to form the first primer layer above the doped layer using Cr.

Claims

1. A microwave dielectric ceramic device comprising:

a ceramic substrate having through slots and/or grooves; and

a metal layer formed on the surface, the bottom and the walls of the groove of the ceramic substrate,

wherein the bonding force between the metal layer and the ceramic substrate is 1kg/cm²And the resistivity of the metal layer is 1.80 [ mu ] omega cm or less.

2. A microwave dielectric ceramic device as claimed in claim 1 wherein the metal layer comprises a metal primer layer attached to the surface, trench bottom and trench walls of the ceramic substrate and a metal thickening layer attached to the metal primer layer.

3. A microwave dielectric ceramic device according to claim 2, wherein the metal primer layer comprises a first primer layer and a second primer layer in this order from inside to outside, the first primer layer and the second primer layer being formed by multi-arc ion plating and having a thickness of 20 to 200 nm.

4. A microwave dielectric ceramic device according to claim 3 wherein the first primer layer is comprised of one or more of Cr, Ni, Ti, Mo, W, Sn and alloys thereof and the second primer layer is comprised of one or more of Ag, Cu, Au, Pt, Al and alloys thereof.

5. A microwave dielectric ceramic device according to claim 3 or 4, wherein the metallic primer layer further comprises a third primer layer formed on the second primer layer by magnetron sputtering, the third primer layer being composed of the same material as the second primer layer and having a thickness of 1 to 3 μm.

6. A microwave dielectric ceramic device according to claim 2, wherein the metal thickening layer is a Cu layer formed by electroplating and has a thickness of 4 to 40 μm.

7. A microwave dielectric ceramic device according to claim 2, further comprising a doped layer located below the surface, trench bottom and trench walls of the ceramic substrate, the metal primer layer being attached to the doped layer, and the doped layer having a thickness of 10nm or less.

8. A microwave dielectric ceramic device according to claim 3 or 4 further comprising a doped layer located below the surface, trench bottom and trench walls of the ceramic substrate, the first primer layer being attached to the doped layer, wherein the doped layer is formed by ion implantation and is comprised of the same material as the first primer layer.

9. A microwave dielectric ceramic device according to claim 1, wherein the microwave dielectric ceramic device comprises a ceramic filter, a ceramic resonator, a ceramic amplifier, a ceramic oscillator, a ceramic mixer, a ceramic wave detector and a ceramic antenna, and the ceramic substrate comprises Al₂O₃Silicate, spinel type ceramics, composite perovskite, BaO-TiO₂Is (Zn, Sn) TiO₄Is BaO-TiO₂-Nb₂O₅System, BaO-Ln₂O₃-TiO₂System, lead-based perovskite system, CaO-Li₂O-Ln₂O₃-TiO₂Is a microwave dielectric ceramic.

10. A method of manufacturing a microwave dielectric ceramic device, comprising:

pretreating a ceramic substrate, wherein the ceramic substrate is provided with a through groove and/or a groove; and

forming metal layers on the surface, bottom and wall of the ceramic substrate to make the bonding force between the metal layers and the ceramic substrate 1kg/cm²And the resistivity of the metal layer is 1.80 [ mu ] omega cm or less.

11. The method of claim 10, wherein the pre-processing comprises: heating the ceramic substrate to a certain temperature, and then keeping the temperature to carry out Hall source treatment, so that the treated ceramic substrate has a surface tension coefficient of more than 60 dyn/cm.

12. The method of claim 10, wherein forming a metal layer comprises: forming a first priming layer on the surface, the groove bottom and the groove wall of the ceramic substrate by using a first material through multi-arc ion plating, and then forming a second priming layer on the first priming layer by using a second material, wherein the first priming layer and the second priming layer form a metal priming layer.

13. The method of claim 12, wherein forming a metal layer further comprises: forming a third underlying layer on the second underlying layer by using the second material through magnetron sputtering,

wherein the first, second and third primer layers constitute a metal primer layer.

14. The method of claim 12, further comprising: before forming the first primer layer, implanting the first material below the surface, the groove bottom and the groove wall of the ceramic substrate by ion implantation to form a doped layer, wherein the thickness of the doped layer is less than or equal to 10 nm.

15. The method according to any one of claims 12 to 14, wherein the first material is selected from one or more of Cr, Ni, Ti, Mo, W, Sn and alloys thereof, the second material is selected from one or more of Ag, Cu, Au, Pt, Al and alloys thereof, and the first and second primer layers have a thickness of 20 to 200nm and the third primer layer has a thickness of 1 to 3 μ ι η.

16. The method of claim 12 or 13, wherein forming the metal layer further comprises: forming a metal thickening layer on the metal base layer by electroplating, wherein the metal thickening layer is composed of Cu and has a thickness of 4-40 μm.